ptp_pch: Load module automatically if ID matches

The driver can't be loaded automatically because it misses
module alias to be provided. Add corresponding MODULE_DEVICE_TABLE()
call to the driver.

Fixes: 863d08ec ("supports eg20t ptp clock")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>